[求助]新手求助~（关于初级的神经网络问题） [复制链接]

各位大虾，我在网上看到的教程里的一个程序段，本来想要试试看的： )5b_>Uy  
net=newff([-1 2; 0 5],[3,1],{'tansig','purelin'},'traingd'); D;!sH?J@+  
net.trainParam.show = 50; Y_Gd_+oJ  
net.trainParam.lr = 0.05; 9;L4\  
net.trainParam.epochs = 300; mEJ7e#  
net.trainParam.goal = 1e-5; XKTDBaON  
p = [-1 -1 2 2;0 5 0 5]; Leb Kzqe  
t = [-1 -1 1 1]; ]Uwp\2Bc  
net=train(net,p,t); %f'pAc|#  
TRAINGD, Epoch 0/300, MSE 1.59423/1e-05, Gradient 2.76799/1e-10 Gt&yz"?D  
TRAINGD, Epoch 50/300, MSE 0.00236382/1e-05, Gradient 0.0495292/1e-10 tKt}]KHV  
TRAINGD, Epoch 100/300, MSE 0.000435947/1e-05, Gradient 0.0161202/1e-10 ytY\&m  
TRAINGD, Epoch 150/300, MSE 8.68462e-05/1e-05, Gradient 0.00769588/1e-10 ^^v3iCT  
TRAINGD, Epoch 200/300, MSE 1.45042e-05/1e-05, Gradient 0.00325667/1e-10 L"'=[O~  
TRAINGD, Epoch 211/300, MSE 9.64816e-06/1e-05, Gradient 0.00266775/1e-10 BHY-fb@R]H  
TRAINGD, Performance goal met. :=hL}(~]  
a = sim(net,p) QG*hQh  
plot(p,t,p,a,'o') o:#jvi84F  
但是为什么老是报错： 5&8BO1V.  
??? Input argument "net" is undefined. J920A^)j!